Mockito vs. Mocking the JVM: Bytecode Manipulation for Ultimate Test Control

Mockito is the go-to mocking framework for Java developers, but it has limits—it can’t mock final classes, static methods, or native calls. When you need to test legacy code or tightly coupled systems, these restrictions become painful. This is where bytecode manipulation comes in. Tools like ByteBuddy and Javassist allow you to rewrite classes at runtime, bypassing Java’s restrictions. And if …